Evil Step-sisters
In the usual Cinderella story, she is plagued by her two evil step-sisters.
Creation
The evil step-sisters have been an iconic part of the Cinderella story since it's inception, however through the centuries, the sisters names often alter. Starting off as Katherine and Margarete, however would eventually change over to Tisbe and Clorinda due to language translation and were renamed to Drizella and Anastasia in Disney's Cinderella. On Disney's Once Upon A Time, both Tisbe, Clorinda and Drizella, Anastasia make an appearance as different characters.
Although due to those names being the creation of Disney, they are often changed to either the first depiction of the sisters, or are given completely new names.
Major Story Arcs
Typically they vie for the attention of the charming prince before he chooses Cinderella. Although in some depictions, one of the sisters is sympathetic to their sister, however as to which one, it typically alters.